1120 



Journal of Applied Microscopy 



Fig. 1. 



stalks always projected above the water. After five or six weeks, plasmodia from 

 several centimeters to several inches in length were seen to spread out upon the 

 surface of the beaker. They seem to prefer the smooth surface of the glass, 

 perhaps because it offers the only large surface above the water upon which the 

 Plasmodia can spread. From two to twelve days after their appearance on the 

 glass above the water, the protoplasm collects at one or a number of the points 

 at the periphery of the network and forms sporangia, leaving behind the 

 so-called hypothallus. 



Acting upon this suggestion, a series of cultures were made by partly filling 

 beakers with hay, then slipping glass slides between the hay and the surface 

 of the beaker, and adding water until it stood a little above the middle of the 

 slides. Each beaker was covered with a glass plate to prevent too rapid 

 evaporation (Fig. 1). The beakers were allowed to stand 

 undisturbed until the plasmodia appeared. During the time, 

 however, the glass plate was removed for an hour each 

 morning, for fear there might otherwise be too great an 

 accumulation of CO 2 in the beaker. But no further pre- 

 cautions were taken. Other cultures of the same hay were 

 prepared every five days, in that way the various stages of 

 development could be studied or compared at any desired 

 time. It was found that the plasmodia spread as readily 

 upon the glass slide, on the side turned toward the surface of the beaker, as on 

 the beaker itself. At any time, therefore, a slide could be taken from the beaker 

 and studied under the microscope in its undisturbed condition. It is better not 

 to cover the plasmodium with a cover-glass, as it does not live under water, but 

 just at the surface, and either from the pressure of the cover-glass or the excess 

 of water, it is apt to go all to pieces. Very little of the hay infusion need be 

 added from time to time to keep the uncovered plasmodium moist. 



A form which was found most suitable to study the streaming movements of 

 the protoplasm developed in cultures made from hay gathered in Aurora, N. Y., 

 during 1S98. This same hay is still used in the laboratory, and produces plas- 

 modia as rapidly as it did the first year it was gathered. I have not been able 

 to identify the form 

 illustrated two-thirds 

 its natural size in Fig. 2 

 and enlarged in Fig. 3. 

 It is of an opaque 

 r"'?:- ■-■ cream white color and 



always forms as figured, with a strong 

 branch just at the surface of the water, 

 sending down secondary branches 

 somewhat smaller in size, which con- 

 nect by still smaller branches with a 

 very vacuolated network just within 

 the water. Under the microscope the 

 clear hyaloplasm zone and the granular inner zone can be easily distinguished ; 



Fig. 3. 



